Peter Carey speaking at the Guardian book club. Photograph: David Levene

I once lived in a house designed by the great architect Richard Leplastrier. It was small, modern, vernacular and far cheaper than I would admit. It perched on its long tree trunk legs on the banks of the flood-prone Never Never river. To inhabit the house was to live connected to this lovely gin-clear stream at the back, and the towering walls of the Dorrigo escarpment at the front.

The river provided a constant song, gentle swimming holes, violent floods. The escarpment brought dancing lightning storms along its ridge.

Driving from the town of Bellingen you took the road to "the Promised Land" where you found the whole valley spread before you: the line of casuarinas tracing the course of the Never Never, the high back wall of the escarpment looming two thousand feet above, and a perfectly placed small, white clapboard church, sited a little above the river, beyond the reach of flood.

I was certainly not a Christian. But it was satisfying to see how the church sat in its place.

Then the Bishop of Grafton revealed he had plans to remove the church. It was a bottom-line issue. Insufficient money in the plate.

For someone whose most religious observance was getting stoned and watching the lightning storms, it was peculiar that this news should so upset me. Had I been, perhaps secretly, comforted by the church? Was I, in some way I could not admit, still vitally connected to the Christian stories of my youth? I had certainly grown up asking God to bless mummy and daddy. I had squirmed while I endured my mother's very loud Holy Holy Holys. I had been transported to a school for "Christian Gentlemen". I once kept score of God's responses to my prayers.

So: was the church still offering me some childhood comforts? I thought, maybe. I thought, probably not. However, if I had a culture at all then it seemed to be a Christian one. It was certainly Christian stories that had driven out the Aboriginal stories from the places I had lived, and one could look across the Promised Land and know that, two hundred years ­before, it had been filled with Aboriginal ­stories. The tribes who told them were all gone, but it was a safe bet that the Never Never river was a story, that the Dorrigo escarpment was a story, that the wedgetail eagle, soaring in the updraft on the cliff face, was a story too. The valley had been a cathedral in another time.

For the sake of the Christian stories, these other stories had been poisoned, shot and drowned.

And now we had no use for the Christian stories and the church would be physically removed. Then the site would be scarred and broken and in these broken places thistles would grow.

How absolutely perfect, the novelist thought – nothing could better represent the emptiness of our present beliefs, the beliefs we had killed the Aboriginal stories for.

At this stage, while the local community split into two groups to bid against each other to see who would pay the most money to the Bishop of Grafton to leave the church just where it was, I was envisaging the small, white clapboard church as a box full of Christian stories. I was imagining the moment that box of Christian stories came floating or cutting through the landscape filled with Aboriginal stories.

I had no idea about Oscar, no clue about Lucinda, but I thought: this is a novel.

But of course it was ridiculous. Why would anyone float a church along a river? Might it be to demonstrate some prefabricated building method for pioneers? Might it be a bet? What about Pascal? Didn't he say to believe in God was to make a bet? (If you were right, if there was a god, you won big time. If you were wrong, you'd lived a good life just the same.) I thought of betting, poker, chance, the Bible, the Melbourne Cup, drawing lots, the ­notion that chance was the wish of God. But why would anyone build a church like that?

I talked to my friend Richard Leplastrier. I said, didn't the Victorians have some prefabricated technology that involved cast iron?

They did, he said, but only for glass-houses. Why do you want to know?

So I told him.

And he said, well, why don't you have a glass church?

At that moment I still didn't know who Lucinda was or how she would inherit her glassworks, and I couldn't even glimpse Oscar, whose acceptance of the Anglican communion would be an improbable act of rebellion, but I knew I had Folly and I knew I had Obsession and some painful truth about my country – in short, something to occupy me for the next two years.